Britain prepares for a momentous vote Thursday that will decide whether it leaves the European Union. The debate has centered on immigration and economic security and has often been bitter. Both sides have lowered the tone of their arguments after a three-day suspension of campaigning that followed the murder of an anti-Brexit lawmaker, an incident that polls indicate has shocked many previously undecided voters who now say they will vote to remain.

These are uncertain times in a nation whose economy is the second largest in the European Union. The stakes are huge.

There are warnings that leaving the 28-member bloc may cause the British pound to lose 15 percent of its value and bring the resignation of David Cameron, the country’s prime minister, whose mandate depends on whether Britain listens to him and votes to remain.

“If we choose to leave, we can leave. But let us be clear - if we do leave, that is it. We are walking out the door,” said Cameron.

For such an important election, many voters complain there has been too little solid information to make a decision and too much scaremongering, and grandstanding by both sides. Flotillas of the “Leave” and “Remain” camps recently faced off on the River Thames.

For months, the Leave campaign has been hitting the streets. Its arguments are based largely on immigration, and the belief that Britain has handed control of its borders to a European super state.

“The U.K. has lost control over migration. We have to accept anyone into this country if they have an EU passport, no matter if they have a criminal record or not. We are not allowed to say ‘no’ to people and that is damaging for the security of the U.K., but it is also putting pressure on jobs and opportunities for young people,” said Tom Harwood, a Brexit campaigner.

Sidewalk memorials have gone up throughout Britain in honor of lawmaker Jo Cox, whose murder last week allegedly by a far right extremist with mental problems has been followed by a jump in support for remaining in the EU. (L. Ramirez/VOA)

The murder of Jo Cox, an anti-Brexit, pro-immigrant lawmaker allegedly by a far right extremist with a history of mental problems had a sobering effect on both campaigns, and on voters.

“There has been a lot of bad feeling because of the way both the Leave campaign, the Brexiters, and the Remain campaign have acted,” said Mary White, a British voter.

Polls since the June 16th murder showed the Leave camp losing ground, but with both sides still very close on a referendum that many believe could change the course of European history.